[1] Royal Free & UCL, Sch Med, Dept Histopathol, London, England
[2] Inst Canc Res, Gene Cloning Ctr, Sutton, Surrey, England
[3] Inst Portugues Oncol Francisco Gentil, Serv Anat Patol, Oporto, Portugal
[4] Massachusetts Gen Hosp, Dept Pathol, Boston, MA 02114 USA